Hydraulic apparatus



April 11, 1950 I a E. AD MS ETAL. 2,503,985

HYDRAULIC Al rmms 6 Sheets-Sheet 2 Filed Dec. 16, 1947 b EN April 1950 a E. ADAMS mm. 2,503,985

' mmuucuvmws I Filed Dec. 16, 1947 6 Sheets-sheaf 3 INVHVTOR. CECIL E. ADAMS Y IENDELL E.REN|OK c ADAMS ETAL 2,503,985

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HYDRAULIC APPARATUS Filed Dec. 16, 1947 e Sheets-SheefG 4 I I INVENTOR. 76 CE E. ADAMS WEN LL E. RENlCK F 1 6. 5A By Patented Apr. 11, 1950 HYDRAULIC arramrus Cecil E. Adams, Columbus, and Wendell E. Renick, Grove City, Ohio, assignors to The Denison Engineering Company, Columbus, Ohio Application December 16, 1947, Serial No. 791,946

One of the objects of this invention is to provide a hydraulic press with a reciprocating table and a hydraulic system by which the press ram and table are automatically operated to alternately position work-receiving stations on the table in registration with the ram and then perform a cycle of ram movement consisting of pressing and return strokes.

Another object of the invention 'is to provide a hydraulic press with a reciprocating table and a hydraulic system embodying a plurality of automatic control valve mechanisms which are interrelated so that the valve mechanism for controlling the press ram will permit but a single operation of the ram and then direct fluid pressure to the control mechanism for the table to cause movement of the table, the latter control mechanism having an element operated by the table when it reaches a predetermined position to apply fluid pressure to a part of the ram control mechanism' to initiate a cycle of operation of the ram, the initial movement of the ram interrupting further flow. of fluid to the table control mechanism until the cycle of ram movement has been completed. In this manner, all danger of interference between ram and table or apparatus carried thereby will be avoided.

A further object of the invention is to provide a press with a reciprocating table and a hydraulic system for operating the press and table in a certain sequence, the system embodying a table control valve including a casing and a plurality of spool elements certain of which are responsive to fluid pressure to effect the operation thereof and at least one of which is responsive to table motion to select the direction of the next succeeding table movement.

A still further object of the invention is to provide a press with a sliding table and a hydraulic system including a ram control valve having a fluid pressure responsive element for initiating a cycle of operation of the ram and a table control valve having a plurality of spool elements one of which is operated by the table at the termination of movement in either direction to apply fluid pressure to the pressure responsive element in the ram control valve to initiate a cycle of movement of the ram, another spool element in the table 13 Claims. '(01. 607-97) control valve being responsive to fluid pressure to move to a position to direct the entire available pressure supply to the pressure responsive element of the ram control valve to retain the same in position to continue the pressing stroke of the ram until another source of fluid pressure for performing this function becomes available.

Further objects and advantages of the present invention will be apparent from the following'description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Figure 1 is a perspective view 0'1 a press formed in accordance with the present invention, this press being provided with a reciprocating table.

Figure 2 is a front elevational view of the press shown in Fig. 1,

Figure 3 is a side elevational view of such press,

Figures 4 and 5 are detail longitudinal sectional views taken through the reciprocating table on the planes indicated by lines IV-IV and V--V respectively of Figure 3,

Figure 5A is a vertical trahsverse sectional view taken through the table on the plane indicated by the line VA-VA of Fig. 4.

Figure 6 is a diagrammatic view of the hydraulic system and operating mechanism contained therein by which the press and sliding table are operated, the mechanism of the system being shogvn in the positions occupied when the press s is;

Figures 7 to 10 are diagrammatic views of the portion of the hydraulic system employed to operate the table showing the mechanism thereof in various stages of table operation, and

Figure 11 is a detail sectional view showing the power cylinder for moving the table and the table control valve mechanism.

Referring more particularly to the drawings and especially Figures 1 to 3, inclusive, the press forming the subject matter of the invention is more generally shown therein. This press comprises a frame l0 having base, column and head sections ll, l2, and I 3 respectively, and a worksupporting table designated generally by the numeral l4. This work-supporting table is carried by the forward portion of the base section ll beneath the forward portion of the head section l3. This head section of the press contains a power cylinder i 5 in which a ram I6 is received for'sliding movement, the ram projecting downwardly from the head section toward the table. In operation the ram moves toward and away from the table through the operation of the power cylinder.

The press I is provided with a fluid reservoir II, a power-operated pump I8, and a hydraulic system 28 for utilizing the fluid pressure generated by the pump l8. The press is similar in construction and operation to that shown in copending applications Serial Nos. 589,163, flled April 19, 1945, (now Patent No. 2,491,355 issued Dec. 13, 1949) and 682,974, filed July 11, 1946. The press per se includes a control valve mechanism, designated generally by the numeral 2|, used for controlling the operation of the power cylinder l5, both the control valve mechanism and power cylinder being arranged in the hydraulic system 20. The mechanism 2| is also disposed in the head section of the press frame and is provided with an exteriorly arranged operating handle 22; this handle may be employed to cause either a single cycle of operation of the press and sliding table or an automatically repeated series of such cycles. It may also be used to interrupt a cycle of operation when occasion demands.

The movement of handle 22 imparts rotary movement to a disk 23 journalled in the control valve mechanism. This disk carries an eccentrically arranged pin 24 which projects into a bore 25 in the body 26 of the control valve mechanism,

the bore receiving a slidable valve spool 21.

The pin 24 extends into a slot formed in the lower portion of the spool 21 and, due to the eccentric arrangement of the pin, longitudinal movement of the spool will result when the disk 23 is rotated. Spool 21 is normally urged toward a centered position in which it is shown in Figure 6 by coil springs 28 and 30, disposed between the opposite ends of the spool and the bottom and top covers 3| and 32 of the valve body 26. Spool 21 has a reduced intermediate portion 33, the purpose of which will appear as the description proceeds. Body 26 is also provided with a second bore 34 disposed in parallel relationship to the bore 25, the body having a plurality of longitudinally spaced annular grooves 35 to 42, inclusive, extending around the bores 25 and 34, certain of the grooves communicating with bore 25 and the others communicating with bore 34.

Bore 34 also receives a valve spool 43 which is of generally tubular formation and is provided with longitudinally spaced sets of laterally extending ports 44 to 5|, inclusive. Spool 43 receives a second spool 52 which is provided with reduced portions 53, 54, 55 for the purpose of establishing communication between certain sets of the ports in spool 43. Spool 52 is normally urged toward the lower end of the chamber in spool 43 by a coil spring 56 disposed in a socket in spool 52 and engaging a cap 51 employed to close the upper end of spool 43. Spool 52 includes a longitudinal passage 58 extending from the spring socket to the lower end of the spool, this passage being intersected adjacent the lower end of the spool by one or more transversely extending passages 68. The spool 43 has a downwardly extending rod 6| which projects through the lower cap 3| oi' the valve body and extends toward the base section in a recess in the front wall of the column section l2. This rod 6|, which is commonly termed a shipper rod, is provided with one or more collars 62 for engagement by a rearwardlyextending arm 63 carried by the press ram Hi. When the ram is moving in an upward direction and it engages one of the collars 62, it will move the spool 43 upward to the position shown in Figure 6. Normally this spool occupies a slightly lower position inwhich a shoulder 63A thereon coincides with the upper surface of a washer 64 which in turn is yieldably held in engagement with a shoulder 65 in the valve body 26 by a coil spring 66, this coil spring also engaging a collar 61 surrounding the shipper rod 6|. The collar 61 engages a transversely extending pin 68 in the shipper rod and when the shipper rod moves in an upward direction the pin 68 forces the collar 6'! against the spring 66 compressing the same against the washer 64, the spring 66 thus yieldably resists upward movement of the spool 43.

It will be obvious that initial downward movement of the ram 6 will move the arm 63 away from the collar 62 permitting spring 66 to expand and move the shipper rod and the spool 43 downward until collar 61 engages the lower end of a socket in the cap 3|. mechanism 2| are disposed as shown in Figure 6, the press will be idle and the fluid discharged by pump |8 will be directed to the reservoir H, the fluid flowing first to groove 35 through conduit 69 and from groove 35 to the interior of spool 43 through ports 49 and outwardly therefrom through ports 48 to groove 38, which groove communicates with a recess 10 which in turn communicates with bore 25. The fluid will flow upwardly in bore 25 around the reduced portion of spool 21 to the groove 42, this groove communicating with groove 31. The fluid then flows through ports 50 in spool 43 to the interior thereof above spool 52 and outwardly through ports 5| to groove 48. This groove communicates with the upper end of bore 25 which in turn is directly connected with the reservoir l1. When fluid is discharged in this manner, pump l8 will operate under a minimum load.

Valve mechanism 2| constitutes, in eflect, a master valve in that it controls the operation of the entire hydraulic system 20, all fluid flowing from pump l8 passing through this valve before being utilized either in the operation of the power cylinder l5 or the reciprocating table l4. The upper and lower ends of power cylinder l6 are connected by lines II and 12 with grooves 31 and 36, respectively; these lines constitute alternate inlet and exhaust lines depending upon the direction of movement of the piston 13 in the power cylinder IS. The hydraulic system 20 includes another line 14 which extends from recess 18 in valve body 26 to the control valve mechanism indicated generally by the numeral |5A for the reciprocating table l4. Valve mechanism IS-A includes a valve body IS-A which, for convenience in illustrating, has been shown in various figures of the drawing as composed of three separate pieces. It should be obvious that this valve could be of one piece or more depending upon the desires of the manufacturer. Valve body |6-A includes a plurality of bores l5, l6 and IT for the reception of spools I8, and 8|, the first spool 18 being disposed for sliding movement in bore I5, spool 88 being disposed in bore 16 and spool 8| in bore 11. Line 14 extends to an inlet port 82 which in turn is connected with a groove 83 surrounding bore 15. Spool 18 is provided with an external groove 84 which, when the spool is disposed in the position shown in Figure 6, establishes communication between groove 83 and a port 85 connecting with bore I5 in longitudinally spaced relation from groove 83. Spool 18 is normally urged to this position by a coil spring 86 disposed between the spool and one end of bore 15.

Port 85 is connected by a passage 81 with a pair of grooves 88 and 90 formed in the body 16-A 75 around the bore 16, these grooves being spaced When the parts of the control valve 33, and

ves 33 and.

13. when fluid is supplied to line I4 and spools I3, 33 and 3| are disposed as shown-in Figure 6, fluid will be conducted from line I4 through passage groove 33, passage 3|. grooves 93. 95 and age III! to groove IIII and the left end of bor 16. This fluid will exert a force on spool 33 moving the same to the right to the position shown in Figure 7. when spool 33 cccupies this new position, agroove I32 in the exterior thereof will establish communication between groove 33 and groove I03 located adjacent thereto, so that fluid introduced to groove 33 will flow to groove I03 and from this groove throu h passage I04 to another groove I05 surrounding bore 11. This groove its i comiected by line I55 with the outer end of a hollow piston rod IIII which forms a part of a piston and cylinder type fluid motor Ilia employed to move the table I4. In this instance the cylinder III! of motor III is directly connected with the movable portion III of the table while the piston I I2 of such motor and the piston rods I01 and II 3 are held stationary. It will be seen that when the piston and piston rods' are stationarily held, fluid pressure supplied to the cylinder at one or the other end of the piston will react to impart movement to the cylinder and, in this instance,

the table section II'I connected thereto.

This tabl section III is supported for horizonon the member II4; these rods project into the cylinder H0 and engage opposite ends of the piston H2. The inner end portions of the rods I01 and H3 are provided with a series of holes fluid is conducted by conduitlli. to the war II. Itwillbeseenthat,sslongasfluidunder pressure is supplied to cylinder I II and exhausted therefrom in this manner, table III will continue to move toward the left. The movable portion of table III is provided with a yoke member I21 having right and left ends I23 and I33. These ends project laterally into registration with the spool 3I and are so arranged that in the final stage of movement of the table they will mov the spool 3| to the right or left depending upon the direction of movement of the table.

. Figure 8 illustrates the hydraulic system after the table has moved to the left and the laterally projecting end I23 of the yoke has moved spool II to the left. At this time the reduced portion .or groove 36 establishes communication between roove I35 and groove I'3I which groove is disposed between .groove III5 and groove I2I, these grooves all surrounding bore 11. Groove I3I is I connected by a-passage I 32 with one end of bore III through which fluid flows from the rods into the cylinder. A plurality of openings are provided in longitudinally spaced relationship so that, as the table approaches the end of its stroke, the openings will be covered consecutively, thus gradually reducing the discharge of fluid from the end of the chamber toward which the piston is travelling, and the speed of movement of the table. The table will thus start and stop gradually rather than suddenly. When fluid is supplied to one end of the power cylinder in the manner illustrated by the arrows in Figure 7, the table will move, in this instance, toward the left, causing fluid at the right hand end of the piston I I2 to be discharged through the openings in piston rod II3 to the interior thereof. This oil will flow through line I20 to groove I2I which surrounds bore 11 and from this groove through passage I22 to groove I23 surrounding bore 16. Groove I23 is at this time, connected with groove I24 also surrounding bore I5 by an external groove I25 formed in spool 30. From groove I24 15 at the end of spool II. This spool is reduced slightly at this end so that fluid entering from passage I32 may react on the spool to move the same to the end of bore I5 in opposition to the force of spring 36. Spool I3 has been illustrated in this position in Figure 8. When in this position passages formed in the spool will establish communication between port 82 and the end of the bore I5 communicating with passage I32 and fluid supplied to the control valve mechanism "IS-A through line I4 will be immediately directed. through a control port I 33-A into line I33 without flowing to the table motor I08.

Line I33 extends from valve mechanism IL-A to groove 39 in valve body 25. When the spool 43 is in the position occupied when the ram is elevated as shown in Figure 6, ports 44 will be in communication with groove 39 and fluid flowing through line I33 will be directed to groove 39 and through ports 44 to the interior of spool 43' at the lower end of spool 52. This fluid will exert a force on spool 52, to move the same upward in opposition to the spring 55. When the spool 52 occupies its uppermost position the reduced portion 54 will establish communication between ports 43 and ports 50 and fluid supplied to the groove through line will then be directed through ports '50 to groove 31 from which it will flow through line II to the upper end of power cylinder I5; this fluid will exert a downward force on the piston I3 causing the same to move in a downward direction. In so moving, the piston 13 will displace fluid from the lower portion of the power cylinder I5 through line 12 to groove 35. This fluid will flow through ports into passages 60, which will then be in registration with such ports, and through the longitudinal passage in the spool 52 to'the upper end of the chamber in spool 43; this fluid will be exhausted through ports 5| to groove 40 from which it will flow to reservoir I'I. Due to the resistance to fluid flow offered by relatively small longitudinal passage 58 in the spool 52 a back pressure will be created which will b transmitted to the fluid in the spool 43 at the lower end of the spool 52, this back pressure will maintain spool 52 in its elevated position as long as piston I3 is moving in a downward direction.

It will be noted that upon initial downward movement of the piston, spool 43 will be moved downward a slight distance by spring 35 until 'the power source will no longer be supplied to line ll and valve mechanism IS-A. Inasmuch as fluid is no longer supplied to this mechanism there will be no force tending to move table N. All the fluid from the power source will then be available to move piston II and ram It in a downward direction. When the ram engages an obstruction which oflers sumeient resistance to cause the pressure in the upper end of the cylinder l6 and the portion of the hydraulic system between the power cylinder and the pump ll to increase to a previously set valu at which fluid will be discharged through a line I" and relief valve i, the piston 13. will cease to move in a downward direction. When this piston stops moving, the back pressure in the lower portion of cylinder l5, line 12, groove 3!, passage 80 and the lower portion of the chamber in spool 43 will fall permitting spool 52 to be moved in a downward direction to a position establishing communication between ports 49 and H in spool 43. Ports 4! will at this time be in registration with groove 36 and fluid supplied thereto will be directed through conduit 72 to the lower end 'of the power cylinder II. The force of this fluid will move piston 13 in an upward direction causing a return movement of piston I3 which will displace fluid from the upper end of power cylinder I! through line H to groove 3?, this fluid flowing through ports ii) to the interior of spool it above spool 52, such fluid flowing outwardly through ports I to groove 40. This fluid will flow over the path previously mentioned to reservoir 3?.

At this time ram i6 and piston 73 will be moving in an upward direction and in the final stage of movement will, through the arm 53, move shipper rod 55 and spool 43 back to the position illustrated in Figure 6, wherein ports 48 will register with groove 38. As the spool 43 is so moved, communication between ports 41 and groove 36 will be interrupted and fluid will no longer be subplied to the lower end of the power cylinder 5. The ram is will then discontinue moving and be retained in an elevated position. The full pump supply will again be available for the operation of the sliding table.

From Figures 6 to 10, inclusive, it will be observed that the body dB-A is provided at the ends or thebore 15 with cap members in which reduced cylinders see are formed for the slidable reception of small pistons i 31. These pistons have shoulders i333 to limit their inward movement, and reduced extensions which project into the interior of the bore and engage the ends of spool Ed. when spool 8! is moved from one extreme position to the other by the flnal stage of movement oi the reciprocating table and fluid pressure is supplied directly to passage l32, this fluid pressure will be applied through passages E89 and l iiiv to the outer ends of pistons 7, these pistons will be urged inwardly causing the spool 85 to be moved to a centered position in the bore 75. Spool 80 has a reduced longitudinally extending passage I to permit this longitudinal movement, fluid flowing from one end of the bore through the passage Ill to theopposite end. This centering of spool 80 takes place immediately after spool 8i has been moved by the table. This movement is important inasmuch as it assists in determining the direction of movement of the table I ll after the ram has completed its return stroke and fluid is again supplied from the pressure source to line M. This fluid willflow to port 82 in the body ii-A. The system will then be in condition for the return movement of the table, spool 18 having returned to its normal position when the back pressure was dissipated due to the stoppage of the ram at the termination of its power stroke. Fluid thus supplied to port 82 will again be directed through passage 81 to grooves 88 and 90. Upon the initial flow of fluid through line H the parts of the table control valve mechanism It-A will be caused to assume the positions shown in Figure 10, spool 80, being moved to the left by fluid pressure flowing from port 82 through line 87 to groove 90, through passage 92 to groove 9|, through grpove 91 in spool 8| to groove 3 and through passage I to the right hand end of bore 18. when fluid was first supplied to line 14 after ram II had been fully retracted, spool occupied a centered position as shown in Figure 9; fluid supplied to line 74, however, followed the path outlined above to the right hand end of bore I8 and moved the spool 80 to the left to the position shown in Figure 10. when this spool occupies this position, a groove I45 therein establishes communication between groove and groove I23, which is connected by passage I22, groove Hi, and passage in with the outer end of piston rod 3. Fluid supplied to piston rod ii: will flow into the right hand end of cylinder ilil causing the cylinder-and the table Ill connected therewith to move toward the right. When so moving, fluid will be dispelled from the left hand end of cylinder H0 through the piston rod ill'l, line 806, groove I05, passage 804, grooves W3 and 525 to groove 924 from which it will flow through line I26 toreservoir il. When the table approaches the limit of its movement toward the right, end 83!! of yoke 82'! will again shift spool hi to the right to cause the groove 96 thereon to connect grooves Hi and Hi so that fluid under pressure supplied to the valve mechanism IS-A will be directed through passage I32 to the left hand end of bore 55 to again move spool 78 to the right in opposition to the spring 86. When so moved spool 18 or passages formed therein will again establish communication between line id and line 833 so that fluid pressure may be applied to the spool valve 52 to initiate a cycle of operation of the ram.

As previously mentioned, when line I32 is supplied directly with fluid pressure, such fluid pressure will be applied through lines H39 and B to the outer ends of pistons i3! to efiect a centering oi the spool 80. It will be obvious from Figures '7, 8 and 10 that when spool 80 occupies either the right or left extremity of movement only one of the pistons I31 will be active to move the spool. It will also be obvious that after the spool has reached the centered position further movement will be prevented by the piston at the opposite end of the bore.

From the foregoing it will be apparent that the system, which has been shown complete in Figure 6, will operate to efiect movement of the reciprocating table to one extreme position, cause a cycle of operation of the ram including power and return strokes, then effect another movement of the table in the opposite direction, the movements of the table and ram being performed in sequence. Through the provision of the centering mechanism for the spool 80 and the movement of the spool 8i by the table, the direction of each succeeding table movement will be determined. In the event the power should be interrupted causing the press to cease operation at any particular stage other than at the beginning 75 of a cycle of movement, the cycle being per- 4 l1 'fluid supplied to said body to said table motor to move said table in one direction; means actuated by said table adjacent the termination of movement in either direction to move one of said spool members to a new position to direct the fluid to said first-mentioned valve mechanism and apply the same to said flow-directing element to initiate an operation of said ram, certain of said spool members being responsive, when said one spool is in said new position, to fluid pressure to move to another position to cause the succeeding table operation at the termination of the ram cycle.

7. A hydraulic control valve comprising a body, provided with an inlet port, a pair of motor ports, a control port and an exhaust port, said body also having a plurality of bores; a first spool member disposed in one of said bores for sliding movement, said first spool serving in one position to interrupt communication between said inlet and said control port and to establish such communication in another position thereof; second and third spool members arranged for sliding movement in two other bores in said body, said second spool member having actuating extremities extending to the exterior of said body to be actuated by extraneous means, said second and third spools being slidable between two extremities of movement; means engaging said third spool, said means being operative to move the spool to a position intermediate the two extremities of movement thereof, said second spool member serving when in either extreme position to utilize fluid pressure supplied to said inlet port to move said third spool member to an extreme position to establish communication between one motor port and said inlet and the other motor port and said exhaust, movement of said second spool member to the opposite extreme position serving to connect the motor port communicating with said inlet with said control port, said position of said second spool also serving to render the third spool-engaging means operative.

8. Hydraulic control valve mechanism comprising a body provided with an inlet, a pair of cylinder ports, a control port and an exhaust port, said body also having a plurality of bores; a plurality of spool members disposed for sliding movement in said bores, the first of said spool members having actuating extremities extending to the exterior of said body, a second spool serving in either of two positions to connect one of said cylinder ports to said inlet port and the other to said exhaust port: means yieldably urging a third spool toward one position, said third spool being responsive to fluid pressure to move to a position connecting said inlet and said control port; and means operative when said first spool is shifted to cause said second spool to move to a position intermediate said two positions.

9; A hydraulic control valve comprising a body provided with an inlet port, a pair of motor ports, a control port and an exhaust port, said body also lmving a'plurality of bores; a first spool member disposed for sliding movement in one of said bores; means yieldably maintaining said first spool member in position to obstruct communication between said inlet and control ports, said first spool being responsive to fluid pressure to move to a position establishing such communication; second and third spool members arranged for sliding movement in two other bores in said body, said second spool member having actuating extremities extending to the exterior of said body to be operated by extraneous means, said second and third spools being movable between two extreme positions of longitudinal movement; means engaging said third spool, said means being operative to move said third spool to a position intermediate said extreme positions when fluid pressure is applied to said first spool to move the same to a position establishing communication between said inlet and said control Port.

pressure; a reversible fluid motor; control valve mechanism between said fluid pressure source and said motor, said mechanism having relatively movable valve elements operative in one relative position to direct fluid from said source to said motor to cause forward operation thereof and in a second relative position to cause reverse operation of the motor; a second reversible fluid motor; a second control valve mechanism operative to alternately cause forward and reverse operation of said second fluid motor; means actuated by said first fluid motor adjacent the termination of reverse operation for placing the relatively movable valve elements of the flrstmentioned control mechanism in a third relative position wherein new from said source to the first-mentioned fluid motor is interrupted and flow to the second control valve mechanism established; and means in said second control valve mechanism operated by said second motor to direct fluid pressure to the first-mentioned control valve mechanism to place the relatively movable valve elements in the first-mentioned relative position.

11. In a hydraulic system; a source of fluid pressure; a reversible fluid motor; a first control valve mechanism between said fluid pressure source and said motor; a second reversible fluid motor; a second control valve mechanism between the first control valve mechanism and said second fluid motor, said first control valve mechanism being operative to direct fluid from said source to the first-mentioned fluid motor to cause a cycle consisting of forward and reverse operation; means operated by said first fluid motor to actuate said first control valve mechanism to interrupt flow from said source to said first fluid motor and establish a flow tosaid second controlvalve mechanism; means in said second control valve mechanism for selecting the direction of a succeeding operation of said second fluid motor, said means being operated by said second fluid motor at the termination of the preceding operation thereof; and means in said second control valve mechanism for hydraulically actuating said first control valve mechanism to initiate a cycle of operation of said first fluid motor and interrupt the flow of fluid pressure to said secand control valve mechanism.

12. In a hydraulic system, a fluid pressure source; first and second reversible fluid motors; first and second control valve mechanisms, the first control valve mechanism being operative to direct fluid from said source to the first fluid motor to cause a cycle of forward and reverse operation; means operated by said first fluid motor at the termination of reverse operation thereof to actuate said first control mechanism to interrupt fluid flow to the first fluid motor and establish fluid flow to the second fluid motor through the second control mechanism; and means in said second control valve mechanism responsive to the operation of said second fluid motor for redirecting fluid, supplied to said sec- 10. In a hydraulic system, a source of fluid formed when current flow was interrupted will be completed upon the resumption of current flow. With the hydraulic system shown and described the table and ram cycles cannot be performed out of phase. To prevent the building of pressures which might be injurious to the mechanism during the shifting of valve spools in valve mechanism IS-A, a shunt line I46 has been extended from line 81 to reservoir II, this shunt line being provided with a pressure relief valve It will be observed from Figure that the table is provided with a novel work-ejecting mechanism which comprises a slidable pin I48 at each of the work-receiving stages. Such pins are supported for vertical sliding movement and are jointed as at I50 for pivotal movement, such movement being restricted to one direction. As the table moves to the right or left, following a cycle of operation of the ram, the pin I48 moving away from registration with the ram will be moved upwardly by a roller carried by the lower end of the pin moving over a cam surface l5l formed on the support I I4. Due to the pivotal movement of the lower portion of the pin I48, the latter will not be moved when the table moves in the opposite direction.

The table III is provided with shelf extensions I52 which move under stationary plates I53, as the table moves, the shelf extensions I52 serving to prevent the entrance of foreign material into the space occupied by the motor I I 0.

While the form of embodiment of the present invention as herein disclosed constitute a, eferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

We claim:

1. In a hydraulic system, a source of fluid pressure; a power cylinder having a ram; valve mechanism between said source and power cylinder to effect the reciprocation of said ram, said valve mechanism having an element responsive to fluid pressure to initiate the operation of said I being operative to apply fluid pressure to said r pressure responsive element to initiate an operation of said ram.

2. In a hydraulic system, a source of fluid pressure; a fluid motor; valve mechanism between said source and fluid motor, said valve mechanism being automatically operative to cause a cycle of operation of said fluid motor; an element in said valve responsive to fluid pressure to initiate a cycle of operation of said fluid motor; a second fluid motor; a second valve mechanism operative to cause alternate forward and reverse operations of said second fluid motor; and an element in said second valve mechanism actuated by said second fluid motor adjacent the termination of operation in either direction to apply fluid under pressure from said source to the fluid pressure responsive element of said first-mentioned valve mechanism to initiate a cycle of operation of said first-mentioned fluid motor.

3. In a hydraulic system, a source of fluid pressure; a fluid motor; a valve mechanism between said source and said fluid motor; a pair of elements in said valve mechanism operative in certain relative positions to direct fluid from said source to said motor to cause forward and reverse operation thereof and in another relation to direct fluid from said source to an outlet, one of said elements being actuated by fluid pressure; a second fluid motor; a second valve mechanism connected with said outlet; said secand valve mechanism being operative to direct fluid flowin from said outlet to said second motor to cause forward and reverse operation thereof; and a member in said second valve mechanism actuated by said second fluid motor adjacent the termination of operation in either direction to apply fluid flowing from said outlet to the fluid pressure actuated element in said first valve mechanism to initiate a cycle of operation of the first-mentioned fluid motor.

4. In a hydraulic press, a power cylinder; a piston and ram supported for sliding movement in said cylinder; a table disposed for sliding movement to alternately position portions thereof in registration with said ram; mechanism for alternately moving said table and said rain, the latter performing a cycle of pressing and return strokes, said mechanism comprising a source of fluid pressure; a control valve mechanism having a fluid pressure responsive element; a fluid motor connected with said table; a second control valve mechanism for governing the operation of said table; spool valve means in said second control valve mechanism for determining the direction of movement of said table; and a second spool valve element actuated by said table adjacent the termination of movement in either direction to apply fluid pressure to the fluid pressure responsive element of the first-mentioned control valve mechanism.

5. Hydraulic apparatus comprising a frame; a power 'cylinder supported by said frame; a ram received for sliding movement by said power cylinder; a source of fluid pressure; control valve mechanism between said source and said power cylinder, said mechanism having flow-directing means actuated partly by fluid pressure to cause a cycle of movement of said ram and then'direct fluid from said source to an outlet; a second valve mechanism communicatin with said outlet; a table supported for reciprocatory movement on said frame; a fluid motor for actuating said table; spool means in said second valve mechanism operative in one position to direct fluid supplied to said second valve mechanism to said table actuating motor to move said tablein one direction; and means operated in part by said table adjacent the termination of movement in said direction to move said spool means to a second position to apply fluid supplied to said second valve mechanism to the flow-directing means in said first valve mechanism to initiate a cycle of movement of said ram, the spool means being in position to cause reverse movement of said table at the conclusion of the cycle of movement of said ram.

6. Hydraulic apparatus comprising a power cylinder; a ram disposed for sliding movement in said power cylinder; a fluid pressure source; a. valve mechanism between said pressure source and said power cylinder, said valve mechanism having a flow directing element responsive to fluid pressure to initiate the cycles of operation of said ram; a table guided for sliding movement to register certain portions with said ram; a fluid motor for moving said table; valve mechanism for controlling the operation of said table, said last-mentioned valve having a body; a plurality of spool members disposed for movement in said body, said spools cooperating to direct 13 0nd control mechanism, to said flrst control mechanism to actuate the same to reestablish fluid flow to the first fluid motor and interrupt fluid flow to said second control mechanism.

13. In a hydraulic system. a source 01 fluid pressure; first and second reversible fluid motors; a flrst control valve mechanism between said pressure source and the first fluid motor; means in said first control mechanism responsive to fluid pressure to initiate a cycle of forward and reverse operations of said-"first fluid motor; a second control valve mechanism between said first control mechanism and said second' fluid motor; an element in said second control mechanism responsive to fluid pressure to regulate the direction of operation of said second fluid motor; a second element in said second control mechanism, said second element'f'being actuated by said second fluid motor to control the application or fluid pressure to said 'flrst-mentioned element; and a third element in said sec- 14 ond control mechanism operative to direct the entire volume of fluid under pressure flowing to said second control mechanism to the fluid pressure responsive means in said flrst control mechanism to initiate a cycle 01' operation or said flrst v fluid motor.

CECIL E. ADAMS. WENDELL E. RENICK.

REFERENCES CITED The following references are of record in the I flle of this patent:

UNITED STATES PATENTS 

